The present invention relates to a road image display device for generating a road image according to road design data and displaying the generated road image on a display screen.
Recently, there has been developed such a road image display device which is used for displaying a desired road image by scrolling the road image at a specified speed as if one could feel driving a vehicle thereon viewing from a fixed viewpoint and which is applied to simulation for developing an image processing algorithm for recognizing a road from road image ahead of an automatic travelling vehicle, which road image is taken through a video camera attached to the vehicle or which is applied to visual presentation for road design analysis.
The conventional display device generates a desired road image by previously preparing a two-dimensional road image by using a road distance pattern. Consequently, it takes along time to generate the road image.
The conventional device can not generate a road image according to an optional pattern and can not represent actual up-and-down slopes and banks of a road since it has only the ability to produce a two-dimensional road image.
Accordingly, a primary object of the present invention is to provide a road image display device which is provided with means for inputting road design data concerning a straight line area, a clothoid curve (relaxed-curvature curve) area and a circular-arc area for a travelling road distance and means for generating a road image representing a straight-line area, clothoid curve area and a circular-arc area according to the input road design data a and which display device can easily generate any desired road image according to a free road design and, more particularly, can represent an image of curved road portion by a curve having a relaxed curvature for joining a straight-line with a circle of a constant curvature.
Another object of the present invention is to provide a road image display device which is further provided with means for inputting road design data concerning upward and downward slopes and banks for a distance of a travelling road to generate a road image representing upward and downward slopes and banks of the road according the input road design data.
A further object of the present invention is to provide a road image display device which is further provided with means for selectively changing a viewing point position relative to a travelling road image being taken through a camera at a fixed viewpoint and displayed on a display screen by scrolling at a specified speed as if driving thereon to generate a road image being viewed from the selected viewpoint position, thus making it possible to freely produce a road image being viewed from a desired viewpoint that is positioned, e.g., at a specified level on a center line or a left lane on a current road image or produce a road image following the changing of lanes by gradually changing a viewpoint from the right to the left or vice versa.